Involvement of tannase in the acquisition of manganese from tannin-rich medium by tannase-producing Lactobacillus plantarum

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The role of tannase produced by Lactobacillus plantarum in tannin-rich medium was demonstrated by using strains with known tannase activities. After 20 h incubation in aerobic tannin-rich medium, the growth of L. plantarum KOG 19 with low activity was lower than that of L. plantarum ATCC 14917^T with high activity by approximately 1.5 orders of magnitude, whereas the growth of KOG 19 in aerobic medium without tannin was almost the same as that of ATCC 14917^T. The reduced growth of KOG 19 in aerobic tannin-rich medium was recovered by the addition of exogenous tannase or Mn²⁺ to the medium. A similar result was obtained in the comparison of growth levels between high and low tannase activity groups in aerobic tannin-rich medium, while no significant differences were observed between the groups in anaerobic tannin-rich medium. Furthermore, the growth of the low tannase activity group in aerobic tannin-rich medium was restored by the addition of catalase. These results suggest that tannase production allows L. plantarum strains to acquire and accumulate Mn²⁺ which is otherwise chelated by tannins, and then high intracellular Mn²⁺ compensates for the lack of the enzyme superoxide dismutase in L. plantarum resulting in resistance to oxygen toxicity under aerobic conditions.